Fluid meter



Aug. 2s, 1934. w. MLLR 1,972,054

' FLUID IETER Filed octl so, 195s s snms-snm 1 gigi.

Walmrffaller.

u's.28,1934 w. MLLER .1,972,054

y FLUID METER Filed Oct. :50, 19:53 3 Sheets-sheet 2 Aug. 28, 1934.` w.MLLER 1,972,054

FLUID METER Filed oct. so, 195s a sheets-'sheet sA like, by providingPatented Aug. 28, 1934 PAT E N'r ,ori-ICE 1,912,054 FLUID METER WaldemarMller, Berlin-Zehlendorf,

asslgnor to Askania-Werke A. G.

s vormals.

y Central Werkstatt Dessau und Carl Bambergy Friedenau, a German Company'Application october 3o, 1933, serial No. 695,889

. In Germany June 24, 1932 s (c1. 'z3-161) I have filed applications inGermany, June 24, 1932 and June 27, 1932.

This invention relates to meters for measur-v ing the quantity of uid orliquid owing through a tube, chamber or other confined space. .One

of the objects of the invention is to measure the quantity .of fluidilowing through a given space, such as a chamber, tube or the like, by tcreating a parallel iiow of'a current of said fluid, such that thedifferential pressure, causing said current, and acting upon a movablemember shall be proportionally equal tothe quantity of the flow of saidfluid or liquid.

A further object of the invention is to measure the quantity of fluid orliquid flowing through conned space, such as a chamber, tube or the in acurrent of said fluid or liquid, a cylinder and a piston movabletherein,

the diameterV o'f said piston relative to that of said cylinder beingsuch as to produce a parallel larninar'y ilow of said nuid or liquid atthat point, whereby the force exerted upon said pis-v ton by thedifferential pressure producing the flow of said current will beproportionally equal to the quantity`of Vthe flow of said fluidorliquid. h Other objects of the invention will appear from thefollowing description.

The invention and its aims and objects will be readily understood fromthe following descrip- *Y tainedI that is t0 Say,

tion, taken in' connection with the accompanying drawings of severalillustrative embodiments of apparatus for carrying out said inventiomthetrue scope of the invention being set forth in the appended claims. i

Inthe drawingsz. y Fig. 1 is a vertical sectional view of one form ofapparatus for pranticing the inventio Fig. 2 is as ectional view similarto Fig.` k1, but showing a modied form o f indicator and Fig. 3 isanother sectional view similar to Fig.r2, but showing remote indicatorsconnected to the apparatus.

In carrying out my invention, I provide va branch current of 'theliquid, which leaves the tube or other conned space the quantity of the'flow of the liquid 'within which is to be measured,A and rejoins'branch current I provide means, such as a piston or other suitable bodywhich is freely movable in said current, and the diameter of 'whichrelative to that of the space in which is contothe interior diameter ofsaid space, is such that the current ilowing between said piston orother means andthe mirroundingwalls of the space in which it is comlwhere said branch ing'force is of the flow,

the same, and within said flow of liquids teaches that the criticalvalues of Reynolds viscosity and density vdiameter of the tained, `shallconstitute a parallel laminary flow.`

Furthermore, said piston or other means will preferably be connectedtovcompensating means which causes a force to act upon said piston inopposition to that exerted thereon by the pressure of the current, whichlatter of course tends to move said piston in the direction of the flow.the construction and arrangement' being such that said opposing forcewill increasamore and more the greater the displacement of said pistonbythe action of said current.: As said pis-v ton will come to rest assoon as said opposing compensating force balances the force exerted uponsaid piston by said current, the pressure difference created by saidpiston in said current can be measured with the aid of a measuringinstrument for said opposing compensating force. Said measuringinstrument therefore indi-2` cate values which it is desired todetermine, since it is well known that in the case of a parallellaminary flow the pressure drop is proportional to the quantity of theflow itself. Preferably a constriction will be provided in the tube thequantity of liquid flow in which is to be measured, said constrictionbeing between the points current leaves and' rejoins said tubev andwhere a piston is used in said branch current it will preferably becontained in a cylinder provided in said As compared to other, knownmethods using a partial current, the pre `nt measuring apparatuspossesses .this advantage, among others, that by availing ones self ofthe characteristics possessed by a parallel laminary ilow, thecurrent-now pressure and, consequently the opposing compensatdirectlyproportional to the quantity so that the values` of the quantities ofthe flow may be directly read from the indications of an evenlycalibrated measuring instrument without'any further calculations or theuse of intermediate complicated cam or lever devices to terior diameterof the cylinder must be such that a parallel laminary now will beproducedl between said piston and the'interior wall of said'A cylinder.The theory of .the laws governing the flows are determine by thesocalled number. Saidxnum r is dependent upon the.

of the liquid the quantity of the flow of whichis tobe determined. aswell as upon the velocity of the liquider gas and the tube. Said number.can be readily determined'for any given flowing medium and for any sizeof tube by methods which are well known to those skilled in the art andwhich it is unnecessary to go into here. K If the Reynolds number isbelow a' certain figure, the flow will be parallel. Consequently, thepiston should be of such dimensions, according to the viscosity of themedium for which the flowmeasuring means is intended, that the Reynoldsnumber shall be below that gure at which the parallel laminary flowbetween piston and cylinder wall begins.

In the accompanying drawings there is diagrammatically illustratedseveral illustrative emx bodiments of apparatus for carrying out theinvention. Said illustrative embodiments of the invention shown areprimarily intended for measuring thequantity of the ow of liquid fuelsfor engines but it is to be understood that theinvention is not limitedto such use but that the measurement of the quantity of the flow ofother fluids also falls Within the` scope ofthe invention.

Referring to Fig. 1, the tube through which the liquid fuel flows fromthe supply 2 to a carburetor for example, is indicated at 4. Said tube 4is shown as being Aprovided at 6 with a constriction and at said pointsaid tube also communicates with a chamber 8, the upper end of saidchamber-being partially obstructed by a member 10, so that said chambercommunicates with said tube 4 only at opposite sides of said member 10and at the opposite ends of said constriction, to the formation ofAwhich said member 10 contributes. In accordance with the invention,means are provided freely movable in the current of the liquid fuel,said means herein comprising a piston 12 mounted upon a shaft 14slidable in sleeves 16 provided in opposite sides of said chamber 8. Anysuitable conventional packing or other means (not shown) may be providedto prevent leakage around said shaft. Said piston is freely movableaxially of said shaft 14 and its diameter is somewhat less than thetransverse diameter of said chamber 8 which will preferably be in theform of a cylinder. Consequently a branch current branches off from saidtube `4, said current owing between said piston l2 and the walls of saidcylinder and rejoining the main flow in the tube 4, as indicated by thearrows, said branch current, as will be seen, leaving the main tube 4 infront of the constriction 6 and rejoining said tube behind saidconstriction. The diameter of the piston 12 is such that the Reynoldsnumber for the annular space between 'said piston and the inner wall ofthe cylinder is below the limit at which parallel laminary flow begins.Consequently, said piston 12 is'subjected to a differential pressurethat is proportional to the quantity oftfuel flowing through theapparatus. I y

The differential pressure tends. to move'said piston 12 tothe right,referring to the drawing. In accordance with the invention,Vcompensating means are provided to exert upon said piston 12 a force inopposition to that exerted` thereon by said flow pressure. In Fig. 1,said compensating means comprisesa controlling piston 18 and a cylinder20 in which said piston works, said controlling piston 18 being hereinconnected to the shaft or piston rod 14. The interior of said l`cylinder 20 can be supplied lwith a gaseous medium under pressure,preferably compressed air, derived from any suitable conventional sourceof 'Y supply (not shown) and conveyed to the interior ofsaid cylinderthrough a pipe 22, ports 24, 24

walls of said piston 18 to provide a fluid lm be- 42 is pivotedon a.depending ear 43 in the top of the casing and is acted upon by the cuterend of pression spring 44 is arranged between the hand vof the hand.

'connected by a rod 54 to the lever 51.

tween the piston and cylinder and reduce friction. I

lthat at which is located the filter 30, said cylinder 20 is providedwith an opening 32 to atmosphere, and a pipe 34 connects the closed endof said cyl- .inder with a pressure-measuring instrument 36 of anysuitable conventional construction.

Said opening 32 to atmosphere is so placed relative to the wall of thehollow piston 18 that the more said piston is moved to the right,referring to the drawings, the more will said opening be closed, andvice versa. It will be readily understood by those skilled in the artthat the stronger the flow of the liquid in the tube 4 becomes, thegreater will be the difference between the pressures 101, and p2 and thegreater will be the movement communicated to pistons 12 and 18 to theright, referring to the drawings and, consequently, the greater will bethe closure of the outlet opening 32 by the controlling edge of thecontrolling piston 18. There will therefore ultimately be established acondition of equilibrium since less and less compressed air can escapefrom said opening 32, thus increasing the pressure acting against saidcontrolling piston and tending to move the piston 12 to the left. Suchstate of equilibrium will be established when the pressure of thecompressed air within the cylinder 20 balances the pressure differentialacting in the opposite direction upon the piston 12. It will be apparenttherefore that the pressure indicated by the pressure gauge 36 furnishesa measure for the pressure drop of the liquid and therefore a measurefor the quantity of said flow. By suitably selecting the dimension ofthe cross section of the path of flow of the liquid with relation to themean speed or velocity of flow of said liquid, parallel laminary flowwill be secured so that the pressure differential between p1 and p2 willbe proportional to the quantity of flow, thus permitting a linear scalegraduated in terms of quantities of flow tobe used on said pressuregauge or other measuring instrument.

vReferring to the form of apparatus shown in Fig. 2, a casing or housing40 is shown as being formed on or secured to one side of the chamber 8athrough which the piston rod 14a projects. In this instance, hand 41 ofa suitable dial indicator the'piston rod 14a. vTo balance parts in their.normal working position, and to provide for adjustment of thecounteracting pressure, a comand an adjustment screw 45 which is on theaxis of the piston rod. The arrangement is such that the hand may beadjusted to zero and the measuring apparatus calibrated to indicateaccurately the flow .which is `proportional to the movement In Fig. 3,thereis shown another modified formv chamber 52 is also secured to thecasing 50 and 1 carries a sylphon type of diaphragm 53 which is Thearrangementris such that the pressure exerted on the outside of thediaphragmtends to counteract the pressure exerted on the lever 51 by thepiston 15C valve .57. The needlev valve 59 is employed to avoid undueoscillation of the diaphragm and, consequently, the lever 51. 'I'hearrangement is such that the apparatus is balanced when the force ofthepiston rod is equal to the force exerted by the diaphragm action onthe lever 51. The lever 51 is also shown as carrying a plate 60 actingas a valve which cooperates with the nozzle 61 of a passage 62communicating with the :duid inlet passage 56 whichY changes the outletpres,- sure of the measuring fluid. The measured :duid is transmitted toone or more pressure indicators sor gauges 63 which may be arranged onsuitable panels through a suitable conduit 64 which communicates withthe uid passage 58. l

'I'he operation of this type of apparatus is substantially as follows.If the ilow which is to be measured increases, the piston 12b will beacted upon by an increased differential pressure which is directlyproportional to the ow. 'Ihe increased force of the piston rod 14h tendsto move lever 5l counterclockwise and thereby throttles the outlet ofthe nozzle 61. When the nozzle 61 is partially closed, the pressure inthe passages 58 and 62 will therefore increase while the inlet pressureremains the same. The diaphragm 53 therefore exerts increased pressureor force on the lever 51, bringing the system into a new state ofequilibrium. The pressure in the diaphragm chamber 52 will thereforealways be proportional to the action of the piston 12b and likewiseproportional to the ow to be measured. For decreasing flow the action isopposite -to that just described. It is to be understood that any numberof pressure gauges may be used for remote indication of the iiow atdiiferent points.

I am aware that the invention may be -embodied in other specific formswithout departing from the spirit or essential attributes thereof; andlI therefore desire the present embodiments to be considered in allrespects as illustrative and not restrictive, reference being had to theappended claims rather than to the foregoing description to indicate thescope of the invention.

l. Apparatus of the class described comprising, in combination, a tubethrough which ows a liquid the quantity of iiow of which `is to bemeasured; a constriction in said tube; a chamber communicating with saidtube at opposite sides of said constriction; a piston movable in saidchamber, the diameter of said piston relative to the inside diameter ofsaid chamber being such as to create a parallel laminary ow of saidliquid between said piston and the walls of said chamber; a pressuregauge; a cylinder communicating with said pressure-gauge and providedwith an opening to atmosphere, said cylinder being supplied withpressure iiuid; and a compensating piston in said cylinder connected tosaid liirst-named piston to move with the latter responsive tovariations in the diierential pressure in said chamber, variably tocontrol the escape of pressure iiuid through said opening to atmosphere.

2. 'Apparatus of the class described comprising, in combination, aconduit through which flowsa liquid the quantity of flow of which is tobe measured a constriction in said conduit; a by-pass communicating withthe conduit on opposite sides of the constriction' and forming a partialcurrent of said liquid; a body movable in said bye-pass,

the dimensions of said body-being such relative.4 to the interiordimensions of said by pass as toV create a parallel laminary ilow ofsaid liquid past l said body; a pressure gauge; uid prsure responsivemeans connected to act upon said body in opposition to the actionthereon of the differ' ential pressure of the by-passed current; meansto supply pressure uid to-said fluid pressure responsive means and tosaid gauge; and means controlled by s'aid pressure responsive means tovary the pressure of the fluid acting thereon and on said gaugeproportionally to changes in the diierential pressure of the by-nassedliquid.

3. Apparatus of the class described comprising,

in combination, means for conducting a current of the liquid thequantity of ow of which is to be measured, said means including aconstriction for creating a differential pressure; a by-passcommunicating with said means at opposite sides of said constriction;differential pressure responsive means movable in said by-pass andrespon-- sive to the pressure drop in said by-pass and constructed. tocreate a parallel laminary flow of liquid in said by-pass past saiddifferential pressure responsive means; compensating means in operativerelation to said differential pressure responsive means to exert uponthe latter a varying force in opposition to the action thereon of saiddiierential pressure; and means to indicate the strength of said' force.

4. A flow measuring device of the class described comprising, incombination, a conduit for a fluid the flow of which is to be measured,said conduit having a constriction; a by-pass connected to the conduiton opposite sides of the 'constriction and having a chamber throughwhich the by-passed iiuid passes; a piston in said chamber having adiameter of such size relative to the chamber as to create a laminaryflow of the by-passed iiuid; a piston rod projecting through saidchamber; a controlling piston operatively connected to said piston rodand acting in opposition to said rst named piston; a separate source offluid under constant pressure communicating with the cylinder of thecontrolling piston through small ports and acting on said controllingpiston; and a pressure gauge connected to be operated by variations inthe iluid pressure caused by movements of lsaid pistons to indicate thevaried pressure and thereby the quantity of iiuid flowing through saidconduit. 5. A iiow measuring device of thev class described comprising,in combination, a conduit for I which by-passed iiuid passes; a pistonin said chamber having a diameter of such size relative to the chamberas to create a laminary ow of the by-pass'edfluid; a piston rodprojecting through said chamber; a gauge having a hand operable in onedirection by said piston rod; and an'adjustable compression springacting on said hand and piston rod` in opposition to the movement ofsaid piston whereby the movement of the hand indicates the variedpressure` and is proportional to the quantity of flow of fluid throughsaid space.

6. A flow measuring device of the class deconstriction vand having achamber through scribed comprising, in combination, a conduit for aiiuidthe ow of which is to be measured, said to the piston; a. sourceofpressure fluid comconduit having a constriction; a by-pass connectedto said conduit on opposite sides of the constriction and having achamber through which by-passed uid passes; a piston in said chamberhaving a, diameter of such size relative to the chamber as to create alaminary flow4 of the by-passed fluid; a. piston rod projecting throughsaid chamber; a pivoted lever movable in one direction by said pistonrod; a diaphragmconnected to the lever and acting in opposition WALDEMARMLLER.

